With NVIDIA-Linux-x86_64-185.18.31 drivers on 9500GT card (on nForce630a/GeForce7025 its similarly):
1) GLX utility in compiz is enabled, but still in .xsession-errors there are next -
Checking for Xgl: not present.
(in openSUSE11.1 packet "Xgl" is absent at all)
& regularly -
/usr/bin/compiz-manager: line 424: 14583 segmentation error (core dumped) ${COMPIZ_BIN_PATH}${COMPIZ_NA**** $COMPIZ_OPTIONS "$@" $COMPIZ_PLUGINS
(because compiz regularly dumps)
2) when kwin4 effects enabling on KDE3 (on KDE4 I did not check in general as this DE on itself has so huge number of bugs...) with indirect rendering it becomes frozen on some seconds when bringing in the mouse at windows icons in taskbar and with direct - so bug is absent, but .xsession-errors file becomes a very huge (many GB) through some minutes of a hard work with applications windows (with indirect I didn't check this) and, for example, at rotation of a desktop cube its sides disappear.

Is it drivers error or this linux distributive error?
At what moment (on what action) You meant to generate bug report log file?